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E. A. MAYNARD AND P. STANFIELD.

FURNACE.

APPLICATION FILED SEPTA, 19m.

1 ,306,Ql7. Patented June 10, 1919.

2 SHEETS- SHEET I.

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E. A. MAYNARD AND'P. STANHELD,

I FURNACE.

APPLICATION FILED SEPT.4.191B.

1 306,0 1 7., Patented Julie 10, 1919.

2 SHEETS-SHEET 2.

0 pw Jfanf/e/d FEED STATES PATENT @FFEQE.

FURNACE.

Specification of Letters Patent.

Patented June 10, 1919.

Application filed September 4, 1918. Serial No. 252,544.

To all whom it may concern:

Be it known that we, ENNIS ARTHUR MAY- NARD and PERRY STANFIELD,citizens of the United States, both residing at Whittier, in the countyof Los Angeles, State of California, have invented new and usefulImprovements in Furnaces, of which the following is a specification.

This invention relates to furnaces particularly adapted to burningfluid, gaseous or other fuels. Our invention is particularly efficientas applied to fluid or gaseous fuels; and so, in the following describedspecific embodiment of the invention, we explain a specific form of gasfurnace.

It is a primary object of the invention to provide a form of furnace inwhich eflicient combustion may be carried on, and by which the maximumamount of effective heat may be produced by the burning of a givenamount of gaseous or other fuel; and to effectuate this object it is anobject to provide an efficient means for heating the air which supportsthe gaseous or other combustion. This means involves primarily the useof heating tunnels through which the air passes under the floor of thefurnace; the air being thus heated by heat which is otherwise conductedor radiated away from the furnace and usually lost. Means are providedto cause the air to be effectively heated by the gaseous flame; and thetotal result is that the flame and combustion are of much higherefiiciency than is usually possible.

In the drawings we have illustrated two typical forms of furnace, inaccordance with our invention, being furnaces adapted to different typesof boilers; but it will readily be understood that our furnace may beapplied in any situation, by suitable modifications or variations. Inthese drawings Figure 1 is a longitudinal vertical section of one formofour furnace as applied to a water-tube boiler; Fig. 2 is a horizontalsection on line 2-2 of Fig. 1; Fig. 3 is a cross-section on line 33 ofFig. 1; and Fig. 1 is a horizontal section similar to that of Fig. 2showing a modification of the furnace applicable to tire-tube boilers.

Referring first to Figs. 1, 2 and 3: We show therein a furnace structurewhich embodies side walls 10; front wall 11 and rear wall 12, with anintermediate wall 13 which forms the forward wall of the smoke box atthe rear end of the furnace. The boiler tubes 14 set over the front wall11 and over the intermediate wall 13; and the furnace structure properis located between these two walls 11 and 13. On the floor 15 of thefurnace (such floor may be of any suitable material) we erect a numberof longitudinal partition Walls 16 (say three in number) and on thesewalls there is supported an upper furnace floor 17 which is preferablymade up of two courses of fire clay slabs or blocks laid clear acrossthe furnace from side to side. This upper furnace fioor forms, with thelongitudinal wall 16, a plurality of air passages 18. The floor 17 doesnot extend clear to the front wall 11 of the furnace,'but stops short ofthe front wall as do also walls 16; and blocks or slabs 19 may be laidon the forward edge of floor 17 and over the space between the forwardedge of floor 17 and the front wall of the furnace, leaving openings 20directly under the as burners 21; so that the heated air from thepassages 16 will come up directly under the gas burners. The doors 22and 23 on the furnacefront are made so as to be practically alr-tight,and the floor 17 is formed in such a manner as to be air-tight. Theblocks of which the floor is formed may be set in or plastered over witha cementitious clay (a fire-resistant material); and the side walls 10and walls 11 and 13 of the furnace are coated on the inside with aplastering of this clay so as to make the whole of the furnace structurepractically air-tight and allow no ingress of air from below exceptthrough the openings 20. In order to allow for expansion andcontraction, the floor 17 is not laid quite tight at its edges againstthe walls 13 and 10, but a small space is left which is filled with sandasis indicated at 25. This filling of sand makes an air-tight joint andat the same time allows for expanslon and contraction. Such filling neednot neces sarily be used at the back edge at wall 13; the open space atthe front providing for expanslon.

The description so far given is applicable to both the forms of furnaceshown in the drawings; the major difference between these two formsbeing the method in which air is inducted to the passages 18. For thewatertube boiler the air is taken in through side openings 30 in sidewall 10. These openings communicate with passages 31 which, in thepresent construction, are preferably two in number, one passage 31feeding the two passages 18 on the far side of the furnace, and

the other passage 81 feeding the two passages 18 on the near side of thefurnace. At the entrance to each pamage 13 there may be a projectingwall part 32 which partially restricts the entrance to the passage 18;and the flow of air into the passages is controlled by damper doors 33which may be.

raised to make any size opening desired.

Now in Fig. 4 (for the fire-tube boiler) the passages 18 extend clear tothe rear wall 12 of the furnace; and in the rear wall there are inletopenings 80 controlled by damper doors 33 each door and each opening 80serving two passages 18", as indicated.

On the upper furnace floor 13 we lay one or more baffle walls 40composed of brick checker work. These walls are preferably laid on acurved line across the furnace and stand in about. the relation to eachother which is illustrated in the drawings. They do not extend clear upto the tubes of the boiler; and their oflice is to break up and spreadout the gaseous flame so as to keep it from shooting directly throughthe furnace, spreading it out in such a manner as to get most effectivecontact of the flame with the boiler. At the same time this brickchecker Work has the effect of spreading the flame out over the floor 17so as to obtain a more efficient application of the heat to the floor,and so as to most efficiently heat the air passing through the passages18 under that floor. The size and capacity of the passages is such thatthe air necessary for the operation of the furnace may flow relativelyslowly through the passages, so as to have asufiicient time in which .tobe come heated. We have found in one installation that if air isadmitted at the openings 30 at 95 F. it will, in such a construction asshown in Fig. 1, emerge at the openings 20 at about 150 F.; and we havefound that the efficiency of combustion due to this preheating of theair in this manner is in creased by about ten to twelve per cent. Thecomparatively eool incoming air, under the false floor, acts as aninsulating medium to keep the lower floor cool, because this air takesup the heat which would otherwise heat the floor. This is an importantaspect of the invention as applied to marine boilers.

Having described a preferred form of our invention, we claim:

' 1. In a furnace construction, a furnace comprising side and front andrear walls and a floor, a false floor over the furnace floor,longitudinal walls supporting said false floor and forming beneath thatfloor a plurality of air passages, means to induct air to the rear endsof said passages, there being openings through the false floor near thefront wall of the furnace, so that air flows forwardly through 'saidpassages to enter'the furnace, burnersprojecting through the front wallof the furnace over said openings, and brick checker work wallsextending across the furnace above saidfalse floor at a point somewhatrearwardly removed from the front end of the furnace and adapted tospread the flame from the burners over the floor so as to eflicientlyheat the floor and the air passing through the passages beneath it.

2. In a furnace construction, a furnace comprising side and front andrear walls and a floor, a false floor over the furnace floor,longitudinal walls supporting said false floor and forming beneath thatfloor a plurality of air passages, means to induct air to the rear endsof said passages, there being openings through the false floor near thefront Wall of the furnace, so that air flows forwardly through saidpassages to enter the furnace, burners projecting through the front Wallof the furnace over said openings, and brick checker work wallsextending across the furnace above said false floor at a point somewhatrearwardly removed from the front end of the furnace and adapted tospread the flame from the burners over the floor so as to efficientlyheat the floor and the air passing through the passages beneath it; saidmeans for inductingair to the rear ends of said'passages embodyingseparate and independently controllable induction openings feeding theseveral air passages,

3Q In a furnace construction, a furnace comprising side and front andrear walls and a floor, a false floor over the furnace floor,longitudinal walls, supporting said false floor and forming beneath thatfloor a plurality of air passages, means to induct air to the rear endsof said passages, there being openings through the false floor near thefront wall of the furnace, burners over said openings, said false floorending at its edges a little short of the side walls of the furnace, anda filling of sand in the space between the edges of the floor and theside walls to make an air tight joint between the floor and the sideWalls.

4. In a furnace construction, a furnace comprising side and front andrear walls115 and a floor, a false floor over the furnace floor,longitudinal walls supporting said false floor and forming beneath thatfloor a plurality of air passages, means to induct air to the rear endsof said passages, there being openings through the false floor near thefront wall of the furnace over said openings, said false floor ending atits edges a little short of the side walls of the furnace, and a fillingof sand in the space between the edges of the floor and the side walls,said furnace walls and upper floor being air tight so that no air mayenter the furnace 5. In a furnace construction, a furnace comprisingside and front and rear walls and a floor, a false floor over thefurnace floor, said false floor being composed of a plurality of coursesof floor slabs laid in staggered relation on one another so as to shutoff passage of air through said floor, openings through said floorthrough which air may flow to the furnace chamber above, means to inductair into the space below said false floor, said false floor ending atits edges a little short of the side walls of the furnace, and a fillingof a loose finely divided material in the space between the edge-s ofthe floor and the walls of the furnace; so that the false floor is airtight and its juncture with the furnace Walls is air tight.

6. In a furnace construction, a furnace comprising side and front andrear Walls and a floor, a false floor over the furnace floor, inclosingan air passage space over that floor, there being openings through thefalse floor near the front wall of the furnace, burners over saidopenings, means to induct air to the rear end of said air passage spaceso that air entering the furnace passes forwardly through the passagespace, and a checkerwork wall extending across the furnace above thefalse floor at a point between said forward openings and the rear end ofthe false floor and adapted to spread the flame from the burners overthe floor to heat it and the air passing beneath it.

In witness that we claim the foregoing we have hereunto subscribed ournames this 26th day of August 1918.

ENNIS ARTHUR MAYNARD. PERRY STANFIELD.

Witness VIRGINIA I. BERINGER.

Copies of this patent maybe obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

